Melanotropic peptides: Presence in brain of normal and hypophysectomized rats, and subcellularly localized in synaptosomes

✍ Scribed by Dr. Y. Peng Loh; Lloyd Zucker; Hein Verspaget; Tjeerd B. van Wimersma Greidanus

• Publisher: John Wiley and Sons
• Year: 1979
• Tongue: English
• Weight: 666 KB
• Volume: 4
• Category: Article
• ISSN: 0360-4012
• DOI: 10.1002/jnr.490040208

✦ Synopsis

A major and several minor trichloroacetic acid (TCA) soluble, bioassayable melanotropic peptides, as well as bioreactive and inmunoreactive a-MSH have been found in the hypothalamus, olfactory bulb and cerebral cortex of normal and hypophysectomized rats. By employing subcellular fractionation procedures it was demonstrated that a-MSH and the major TCA soluble melanotropic peptide (MMPB) were localized in synaptosomes and were released by hypoosmotic shock. The analysis of MMPR by electrophorctic and chromatographic procedures reveals that it is not ACTH4-lo,ACTHI.lo, AC'rHI-24, N A C A C T H ~-, ~ or a-MSH. MMPB was found to cross-react with an antiserum specific for the Lys-Pro-Val NH2 sequence in a-MSII, indicating that this C-terminal sequence or a-MSH may be present in its structure. MMPB was also shown t o differ electroplioretically from the two major TCA soluble melanotropic peptides found in the neurointcrmediate lobe of the pituitary. In view of their synaptosomal localizations MMPR and a-MSH may play a role in synaptic function in the nervous system.